Drill bit



Sept. 9, 1958 Filed April 27, 1954 E G. BOICE DRILL BIT 2 Sheets-Sheet lf/w/v 6. Bo/ce INVENTOR.

E. G. BOICE Sept. 9, 1958 DRILL BIT 2 Sheets-Sheet 2 Filed April 27,1954 f/V/f) 6. Bo/ce v INVENTOR.

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ATTORNEYS United States Patent DRILL BIT Elvin G. Boice, Houston, Tex.,assignor to Reed Roller Bit Company, Houston, Tex., a corporation ofTexas Application April 27, 1954, Serial N0. 425,889

7 Claims. (Cl. 255-347) This invention relates generally to drill bits,and more particularly to bits for deepwell drilling.

One of the general objects of the invention is to provide a new andimproved drill that will more efficiently drill hard and medium-hardformations.

Another object of the invention is to provide new and improved welldrill rollers having the teeth thereon arranged to produce a moreeffective action in disintegrating material at the bottom of the wellbeing drilled.

A further object is to provide a well drill roller having teeth 'theronwhich may be connected together by a web that extends radially beyondthe teeth, to support and cooperate with the teeth during the drillingoperation.

A further object is to provide a new and improved well drill rollerwherein the teeth or cutting elements on the same roller may engage theformation simultaneously at diiferent levels, in order to facilitate theremoval of particles of the formation at the bottom of the bore holebeing drilled.

A further object is to provide a new and improved well drill rollerhaving teeth thereon, and wherein, on the same roller, a cutting elementextends radially beyond the teeth on the roller so that during thedrilling operation the extended cutting element will cut a narrowcircular groove in the formation at the bottom of a bore hole therebyreducing the lateral support of the formation circumscribed by thecircular groove, thus facilitating the removal of particles of theformation by the well drill.

Another object is to provide a roller bit that will during the drillingoperation cut a kerf in the gage portion of the bottom of the hole sothat the formation within the area circumscribed by the kerf will not besupported by the surrounding formation and may be removed more readily.

Another object is to provide a new and improved well drill roller havinga more effective form of cutting element to remove the formation fromthe outer gage portion of the bore hole being drilled.

Another object is to provide a new and improved roller having cuttingelements arranged thereon to stabilize the roller during the drillingoperation.

Other objects and advantages of the invention will become apparent fromthe following description and the accompanying drawings wherein are setforth by way of example certain embodiments of the invention.

Fig. l is a bottom plan view of a cross roller bit embodying theinvention.

Fig. 2 is a side elevation view of the bit shown in Fig. 1.

Fig. 3 is a detail view of a side roller showing a circumferentiallyextending web on the gage cutting portion of the roller.

Fig. 4 is a fragmentary section view taken along line 4-4 of Fig. 3.

Fig. 5 is an isometric view of a cone bit embodying the invention.

Fig. 6 is a detail view of a portion of a side roller em- 2,851,253Patented Sept. 9, 1958 bodying the invention showing the roller inoperating position on the formation at the bottom of a bore hole.

Figs. 1 and 2 illustrate a cross roller bit employing a number ofconventional parts and the new and improved rollers provided by theinvention. In these figures, a bit head 1 has the usual threaded shank 2by which the bit may be attached to the lower end of a drill stem (notshown). The head 1 may have the usual depending legs 3, 4, 5 and bridge6 to support the usual pins (not shown) upon which may be rotatablymounted the new and improved cross rollers 7 and 8 and side rollers 9and 10. The cross rollers 7 and 8 each have a row of axially disposedteeth 11 thereon. The outer ends of the teeth 11 are connected togetherby a web or cutting element 12. This web extends radially beyond theteeth 11 as is clearly shown in Figs. 1 and 2.

The side rollers 9 and 10 are similar to each other and to the crossrollers 7 and 8 in construction. The side rollers 9 and 10 each have arow of teeth 13. A web or cutting element 14 connects together the teeth13 at the outer or gage cutting portion of the rollers 9 and 10. The web14 extends radially beyond the teeth 13 of the side rollers 9 and 10 toassist in cutting and maintaining the gage of the bore hole, andsupports the teeth 13, during the operation of the bit.

In operation, a drill bit is attached to the lower end of a drill stem(not shown), and rotated upon the bottom of a bore hole. Thus therollers are caused to rotate, and as weight is-applied to the bit by theweight of the drill stem, the teeth or cutting elements of the rollerswill crush, chip or scrape the formation upon which the bit is rotated.The particles of formation thus dislodged will be carried out of thebore hole by drilling fluid which is pumped down through the drill stemand bit head, returning to the surface of the earth in the space betweenthe drill stem and the wall of the bore hole being drilled.

One of the most important desired functions of the side rollers 9 and 10is to cut and maintain the gage or diameter of the bore hole beingdrilled, so that succeeding drill bits, or other equipment, can belowered to the bottom of the bore hole without having to ream down anundergage hole. The gage portion of the bore hole is diflicult to removeand maintain because the formation at the gage or outer portion of thebore hole is supported by the side wall of the hole thus making it morediflicult to dislodge, also, there is more material to be removed fromthe gage or outer portion of the bore hole because it is a greaterdistance from the center or the bore hole.

In my invention I provide more efiicient cutting ele ment arrangement tocut and maintain the gage of the bore hole by providing more material atthe outer or gage cutting portions of the side rollers 9 and It) in theform of a radially extended web 14. This web 14 cuts a narrow kerf inthe formation thereby reducing the support of the formationcircumscribed by the kerf making it easier to disintegrate and removefrom the hole bottom by the drill bit.

Also the cross rollers 7 and 8 may be provided with webs to cutadditional kerfs in the formation to permit easier removal thereof.

Also, the webs 14 on the side rollers 9 and 10 and the webs 12 on thecross rollers 7 and 8, rolling in kerfs in the hole bottom stabilize therollers from moving in an outboard or inboard direction with respect tothe drill bit axis of rotation, because the webs act as flanges tendingto keep the rollers in their respective paths during the drillingoperation.

Figs. 3 and 4 show in detail a side roller 9 of the type shown in Figs.1 and 2, and previously described. The roller 9 has a circumferentialrow of teeth 13 and a. circumferentially extending web 14 connecting theouter ends of the teeth 13 together. The web 14 extends radialice 1ybeyond the teeth 13 as is clearly shown in Figs. 3 and 4.

Fig. 5 shows a cone bitemploying the new and improved substantiallyconical rollers 15. The roller 15 has circumferentially disposed rows ofteeth 16 and a circumferentially extending web or cutting element 17connecting the ends of teeth 16 in the same row together. The web 17extends radially of the roller beyond the teeth 16. The web 17 thusserves to support the teeth, and to cut a narrow kerf in the formationduring the drilling operation.

Fig. 6 is a typical illustration of the action of the new and improvedroller upon the formation. A portion of the side roller 9 having teeth13 and web 14 is shown in operating position on the bottom of a borehole. The web 14 is shown producing a kerf 18 in the formation A, andthe teeth 13 are shown operating on the formation within the areadefined by the kerf 18 but at a different level. The web 14- serves tocut and maintain the bore of the hole B.

In the actual use of a well drill employing the new and improvedrollers, I have found that the cutting elements on the roller drillfaster and tend to retain their original configuration and relationship.Even when the cutting elements are approximately half-worn away, the webstill extends radially beyond the other cutting elements on the sameroller.

It will be understood that the invention is not limited to theparticular embodiments herein shown and described. Various changeswithin the scope of the following claims will be apparent to thoseskilled in the art.

Having disclosed and described my invention, I claim:

1. A roller bit having a head, a substantially conical roller cutterrotatably mounted in said head, the axis of rotation of said cutterextending downwardly and inwardly substantially toward the longitudinalaxis of said head, the base end of said cutter being outermost, saidcutter having a circumferentially extending web at its base end todefine the wall of the hole by cutting a kerf in the gage portion of thebottom of the hole and teeth connected to said web and extendinginwardly longitudinally of said cutter to operate upon the formation atthe bottom of the hole within the area circumscribed by said kerf saidweb extending radially beyond the cutting edge of the teeth.

2. A roller bit having a head, a roller cutter rotatably mounted in saidhead, the axis of rotation of said cutter extending downwardly andinwardly substantially toward the longitudinal axis of said head, saidcutter having a circumferentially extending web at its outermost end todefine the wall of the hole by cutting a kerf in the gage portion of thebottom of the hole and teeth connected to said web and extendinginwardly longitudinally of said cutter to operate upon the formation atthe bottom of the hole within the area circumscribed by said kerf saidweb extending radially beyond the cutting edge of the teeth.

3. A roller bit having a head, a roller cutter rotatably mounted in saidhead, the axis of rotation of said cutter extending downwardly andinwardly substantially toward the longitudinal axis of said head, saidcutter having a circumferentially extending web at its outermost end tocut a kerf in the gage portion of the bottom of the hole and teethextending inwardly longitudinally of said cutter to operate upon theformation at the bottom of the hole within the area circumscribed bysaid cutter said web extending radially beyond the cutting edge of saidteeth.

4. A roller bit having a head, a roller cutter rotatably mounted in saidhead, the axis of rotation of said cutter extending downwardly andinwardly substantially toward the longitudinal axis of said head, saidcutter having circumferentially extending cutting means at its outermostend to cut a kerf in the gage portion of the bottom of the hole andmeans to operate upon the formation at the bottom of the hole Within thearea circumscribed by said kerf said first mentioned means extendingradially beyond the cutting edge of said second mentioned means.

5. A drill bit comprising a bit head, cross rollers and gauge rollersrotatively mounted in the lower portion thereof, each of said gaugerollers having teeth thereon extending longitudinally thereof, andhaving an annular web at its base and connecting the said teethtogether, said web extending radially beyond the cutting edge of saidteeth to cut a kerf in the gauge portion of the bottom of the hole.

6. A roller bit comprising a head, a roller rotatively supported in saidhead, the said roller having a row of axially disposed teeth thereon, anannular web connecting the outer ends of said teeth together at theoutermost end of said roller, the said web extending radially"substantially axially extending teeth thereon, that imbeyond thecutting edge of said teeth to cut a kerf in the gauge portion of thebottom of the hole.

7. In a roller bit comprising a head, a roller cutter rotativelysupported in said head, the said cutter having References Cited in thefile of this patent UNITED STATES PATENTS 1,143,275 Hughes June 15, 19151,905,165 Fletcher Apr. 25, 1933 2,184,066 Zublin Dec. 19, 19392,248,340 Catland July 8, 1941 2,527,838 Morlan et al. Oct. 31, 19502,660,405 Scott et al Nov. 24, 1953

